19 Dec
2017
19 Dec
'17
10:44 a.m.
On Tue, 19 Dec 2017, Víctor López Juan wrote:
I'm thinking that `disjoint` is already a negation: (dis- (not) + joint (united)). When composing with `not`, the user gets a double negation `not (disjoint x y)`. There is a then a small mental effort required to go from "not disjoint" to "overlapping".
If we are going to have only one of the two properties, I would rather have the positive one (`overlaps`) as primitive. Then `disjoint` would be written "not (overlaps x y)", which reads quite easily. (Or even "not (x `overlaps` y)").
I also dislike double negation and think that 'disjoint' is one. I'd prefer to see both 'overlap' and 'disjoint'.